40 replies to this topic

[sam138]

I’ve fitted the camshaft and timing gear on and started to rotate the engine and con rod edge on cylinder 2&3 on there rotation get jammed and catch on the cam lobe pictures below.
Cylinder four con rod also catches slightly but not so bad.
Any suggestions how to correct this ? Can the edge of the con rod be machined slightly on the edge ?


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Edited by sam138, 09 February 2022 - 10:57 PM.

[KTS]

First thing to do is to make sure the cam and crank pulley alignment is correct (i.e dot to dot), and the timing chain fitted

Edited by KTS, 09 February 2022 - 11:06 PM.

[GraemeC]

As above - if the timing is not set this can happen. 

Follow the manual to get the cam and crank in roughly the correct positions before fitting the sprockets and chain, dot to dot.  Then when you turn it over everything will clear.

[sam138]

Thanks, I've re fitted the duplex timing set with engine at TDC and it now clears the camshaft lobes!  As per picture below the issue I now have is with the crank at TDC on cylinder 1 I've fitted the non adjustable duplex timing kit as linked below but the dot to dot are out by half a tooth maybe. The duplex timing chain is also quite loose. Do i need to purchase an alterative chain as I understand you don't use a tensioner with this type ? 

 

 

C-AJJ3325 - Mini duplex chain and steel gears lightened set (minispares.com)

 

 

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Edited by sam138, 10 February 2022 - 12:07 PM.

[GraemeC]

I's say you were one tooth out on the cam sprocket.

 

Traditionally the duplex set up did not have a tensioner and the chain is a little baggy. You can use the simplex tensioner although it doesn't touch across the whole width of the chain so the pad does wear a bit unevenly.

[mini13]

Ive had the cam contact the rod when I inadvertantly timed to BTDC instead of ATDC ( or is that the other way round ) ... anyway double check you've timed it right.

[sam138]

Thanks for the reply's, could someone explain to me step by step how to use a Dial indicator to get the correct TDC please ? I've looked on various YouTube videos but still a bit confused. 

[GraemeC]

If you're only timing using dot to do then its not worth going to that level - as long as the piston is as near the top of the bore as you can get it be eye/feel you'll be OK

[KTS]

Thanks for the reply's, could someone explain to me step by step how to use a Dial indicator to get the correct TDC please ? I've looked on various YouTube videos but still a bit confused. 

 

with a timing protractor on the crankshaft nose and a bit of wire as a pointer set up..

 

rotate crank to bring piston #1 to approximate tdc

 

zero the DTI on #1 piston at TDC and set cam protractor/pointer to TDC/zero degrees

 

turn crank anti-clockwise 'til  DTI shows 10thou deviation (before TDC).  Make a note of the reading on the cam protractor

 

turn crank clockwise back through TDC until DTI shows 10thou deviation (after TDC).  Make a note of the reading on the cam protractor

 

TDC is calculated as being exactly half way between the two readings you've taken

 

for example if reading 1 shows 345 degrees and reading 2 shows 5 degrees, then the piston is actually at TDC when the degree wheel shows 355 degrees

 

now rotate the crank 'til it reads 355 degrees on the pointer (piston1 is now at TDC), and then rotate the cam protractor on the crank to line up the TDC mark with the pointer - the cam protractor/degree wheel is now calibrated to the crank and can be used to time in the camshaft

[Spider]

I'm thinking that yr one tooth out on the big sprocket.

Might need to check the keyways and their indexing to the dots against your old gears, if you have them.

 

The chain does look excessively loose to me, Has the black had the Mains line bored ?

[sam138]

The engine block was given to me by a family friend which was freshly built up a few years ago to my knowledge the block hasn’t had the mains lined bored. I’ve dismantled the block and check everything is new and re torqued and lubed all parts etc as needed.

Is there a solution to the slack in the timing chain ? Going back to an upgraded simplex with tensioner to take up the slack ?

Unfortunately I don’t have any old timing gear for the engine so can’t check this.

Edited by sam138, 11 February 2022 - 10:23 AM.

[sam138]

The engine block was given to me by a family friend which was freshly built up a few years ago to my knowledge the block hasn’t had the mains lined bored. I’ve dismantled the block and check everything is new and re torqued and lubed all parts etc as needed.

Is there a solution to the slack in the timing chain ? Going back to an upgraded simplex with tensioner to take up the slack ?

Unfortunately I don’t have any old timing gear for the engine so can’t check this.

 

Edited by sam138, Today, 10:22 AM.

[KTS]

IWIS chains seem to have a good reputation, so might be worth considering, but also worth noting that the tensioner will fit with a duplex chainset fitted- the only issue is that the pad does not quite cover the full width of the duplex chain

 

[sam138]

Thanks for the reply, I've guessing you mean the below link chain ? so swapping it over to the simplex with the below chain and a tensioner ? does it mean I have a fault with this engine block as the duplex chain is very loose ? 

 

Just to confirm you can use an upgraded simplex set up on a big bore 1380cc ? 

 

Iwis timing chain — Crafted Classics Tuning

 

 

I note Minispares also do an EVO simplex kit 

 

MSSK051EVO - Mini simplex tensioner 6 piece special kit (minispares.com)

Edited by sam138, 11 February 2022 - 11:31 AM.

[KTS]

i'm not suggesting you switch to a simplex setup, just that a different chain and/or fitting a tensioner are options you could consider